Interestingly as they mature I notice they all get a black line or two on their dorsal and anal fins, always on the ray that leads to the tip of the fin. Nick has it, his dad had it, it's strange how a seemingly randomized gene can make a seemingly hereditary pattern. Some get black lips or gill membranes, or a few dots on their abdomens. I have a batch growing from a pairing of the ones with the most black, and assuming the calico/marble gene is co/incomplete dominant, that batch should marble a bit more than their parents as they mature. It doesn't show well on camera but both the first gen offspring I posted had a bit of black. Not much but the gene's there.
